Metering apparatus for particulate material

ABSTRACT

Metering apparatus for metering feed from a source to another location is provided. The metering apparatus is primarily designed to meter a quantity of a supplement or supplemental components supplied to animal feed for accurate control of the quantity and uniform distribution of the feed. The apparatus includes a bin with a reciprocating gate of a constant stroke movable across a variable discharge opening. The reciprocating gate is driven by a 12-volt DC windshield wiper motor which can be operated off a tractor battery in the field, if desired. The unit preferably is used with 110-volt AC power, in which case a drive motor of an auger supplying feed to the bin of the metering apparatus can be controlled by a sensing paddle in the bin of the apparatus. The reciprocation of the gate through its motor can be controlled by a subtraction counter to determine the number of reciprocations and also by a second sensing paddle in the bin which shuts off the gate motor if the bin becomes empty.

United States Patent [191 Grau [ METERING APPARATUS FOR PARTICULATE MATERIAL [75] Inventor: Theodore H. Grau, Sioux Rapids Iowa [73] Assignee: Toledo Stamping & Manufacturing C0. Toledo, Ohio 1 Filed: Mar. 11, 1974 [2]} Appl No: 449,902

Primary E.\'ammerStanley H. Tollberg Alrumev, Agenr, or Firm-Allen D. Gutchess. Jr,

[ Aug. 5, 1975 [57] ABSTRACT Metering apparatus for metering feed from a source to another location is provided. The metering apparatus is primarily designed to meter a quantity of a supplement or supplemental components supplied to animal feed for accurate Control of the quantity and uniform distribution of the feed. The apparatus includes a bin with a reciprocating gate of a constant stroke movable across a variable discharge opening. The reciprocating gate is driven by a IZ-volt DC windshield wiper motor which can be operated off a tractor battery in the field. if desired. The unit preferably is used with l 10- volt AC power, in which case a drive motor of an auger supplying feed to the bin of the metering apparatus can be controlled by a sensing paddle in the bin of the apparatus. The reciprocation of the gate through its motor can be controlled by a subtraction counter to determine the number of reciprocations and also by a second sensing paddle in the bin which shuts off the gate motor if the bin becomes empty.

13 Claims. 6 Drawing Figures PATENTEU ABS 5 I975 SHEET SHEET PATENTEU AUG 1975 METERING APPARATUS FOR PARTICULATE MATERIAL This invention relates to metering apparatus for controlling a supplement or supplemental components added to animal feed.

In more recent years, the addition of a supplement or supplemental components of one type or another to forage has become more and more common. Such supplement usually has been added by hand with the result that it is neither uniformly distributed over the forage nor is the quantity added known with any degree of ac curacy.

Metering devices have heretofore been known to a limited extent for metering supplement to forage. Some of these have been quite expensive and/or required considerable maintenance, while others have been quite effective. A common way of metering the supplement has been by reciprocating a gate under an opening of a bin containing the supplement, with the degree of reciprocation, or length of stroke, determining the amount of supplement metered or discharged from the bin. A meter of this type is shown in my US. Pat. No. 3,184,108. To obtain proper reciprocation of the gate in such an instance, relatively complex means have been required to achieve a reasonably wide range of adjustment.

The present invention provides metering apparatus for a supplement which utilizes a bin with an opening in the bottom across which a gate is reciprocated with a fixed length stroke. The metering is achieved by a sliding valve plate which controls the area of the bin openings to thereby control the amount of supplement discharged with each stroke of the gate. The gate in this instance is driven by a commercially available, relatively inexpensive, 12volt DC windshield wiper motor which also has the advantage of automatically moving the gate to the closed position whenever the motor is shut off. The motor can be driven directly by the I2- volt system of a tractor battery when in the field. Preferably, however, the new metering apparatus is provided with a transformer or converter which can cmploy I-volt AC power and converts this to l2-volt DC for the motor. When IIO-volt power is used, an electrical outlet on the meter can supply power for an auger motor for feeding the supplement to the bin. The bin has a sensing paddle which controls the operation of the auger motor thereby to control the supply of feed to the bin. The new metering apparatus also can employ a subtraction counter which shuts off the gate motor when reaching zero from a pre-selected number, and the bin can have a second sensing paddle which shuts off the gate motor if the bin is empty. In addition to the subtraction counter, a cumulative counter can also be operated to provide the farmer or other operator with an overall indication of the quantity dispensed. Both counters can be operated by a single member which is movable with the reciprocating gate.

It is, therefore, a principal object of the invention to provide improved metering apparatus for controlling the addition of a supplement to forage.

Another object of the invention is to provide meter ing apparatus of the type described which can employ either I2-volt DC or IIO-volt AC power.

A further object of the invention is to provide metering apparatus which has a bin with an opening, the area of which can be controlled, with a gate of fixed stroke reciprocated across the opening.

Still another object of the invention is to provide metering apparatus having a sensing paddle in a bin which is effective to turn on and off a supply motor which supplies particulate material to the bin.

Still a further object of the invention is to provide metering apparatus employing a reciprocating gate with a drive motor controlled by a subtraction counter and a sensing paddle in a bin thereof.

Yet another object of the invention is to provide metering apparatus with a reciprocating gate driven by a windshield wiper motor.

Many other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings in which:

FIG. I is a schematic side view in elevation of metering apparatus in accordance with the invention, and means for supplying supplement thereto;

FIG. 2 is a view in perspective of the apparatus of FIG. 1;

FIG. 3 is a somewhat schematic, bottom view of the metering apparatus of FIG. 2',

FIG. 4 is a fragmentary view in vertical cross section taken centrally through the bottom of the apparatus of FIG. 3'.

FIG. 5 is a detailed view in perspective of a counter and control rod of the apparatus of FIG. 3', and

FIG. 6 is a detailed view in perspective of a valve plate control handle.

Referring particularly to FIG. I, supplement metering apparatus according to the invention is indicated at It) and receives supplement from supply means indicated at 12, discharging the supplement at another location, such as onto forage carried along a conveyor below the apparatus 10. The apparatus 10 thereby can supply a metered, known amount of the supplement uniformly to the forage. Thus, the amount of supplement, which is usually relatively expensive compared to the forage supplied thereto can be accurately determined. The supplement is also uniformly distributed so that each animal receives a substantially constant ratio of supplement to feed. In addition, the supplement can be readily adjusted to provide different amounts under different conditions, as desired.

The supply means I2 include a trough I4 containing an auger (not shown), which carries feed up the trough 14 to a discharge spout 16, when driven by a motor 18. The motor requires a llll-volt AC electrical supply and has a power supply line 20 which can be connected to an electrical outlet box 22 on the metering apparatus. The apparatus can be connected to a l I0-volt AC sup ply through a line 24 connected to an extension cord or other suitable source. As used herein, the term I 10 volt AC is intended to denote common household current, which can vary from about volts to volts.

A limit switch 26 is mounted on the side of the metering apparatus 10 and is connected in series with the supply line 24 and the outlet box 22 to control power to the outlet box. The switch 26 has an operating lever 28 which is positioned to be engaged by an arm 30 affixed to a pivot rod 32 extending across a bin 34 of the metering apparatus 10, between opposite side walls 36 and 38 thereof. A load-sensing plate or paddle 40 extends a substantial distance across the bin 34 between the side walls 36 and 38, being pivotally supported by the rod 32. The paddle 40 is located between a baffle 42 and a front wall 44 of the bin 34. With sufficient particulate material, such supplement. between the baf He 42 and the paddle 40, the paddle is moved to the dotted line position of FIG. 1, causing the arm 30 to depress the lever 28 and shut off the switch 26. This ter minates power to the motor 18 and stops the auger.

As the bin 34 subsequently empties to a level below the lower end of the paddle 40, it swings back to the solid line position, raising the arm 30 and closing the switch 26 again to turn on the motor 18. The lever 28 of the switch can be spring-loaded internally within the switch to urge the paddle 40 to the solid line position. or a supplemental spring can be employed for this purpose. With the paddle 40, the amount ofsupplement in the bin 34 can be controlled within a desired range of levels to keep a relatively constant head of the supplement in the bin. A more consistent discharge of the supplement is thereby achieved.

When the supply means 12 is employed, the appara tus can be provided with a top cap 46 (FIG. 2) which covers the entire top of the bin 34 and has an up wardly extending sheet metal spout 48 terminating in a flexible skirt 50 which fits closely with the spout 16 of the auger trough 14. This assures that no dirt or de bris will he accidentally supplied to the top of the bin 34 and also assures that the supplement will not be blown away under windy conditions.

To control the discharge arrangement for the bin 34, a second limit switch 52 having an operating lever 54 is mounted outside the bin, on the side wall 38. The switch lever 54 is engaged by an arm 56 of a pivot rod 58 which extends across the bin 34 between the side walls 36 and 38, being pivotally supported thereby. A second load-sensing plate or paddle 60 is affixed to the pivot rod 58 and is pivotally supported thereby within the bin 34. The paddle 60 is located on the side of the baffle 42 opposite the paddle 40, adjacent a rear wall 62 of the apparatus 10. Under normal operating condi tions, the supplement in the bin 34 moves the paddle 60 to the dotted line position. closing the switch 52, in this instance. If the level falls below the lower end of the paddle 60, the internal switch spring for the lever 54, or an external spring. if used. urges the paddle 60 back to the solid line position of FIG. 1 and opens the switch 52. This shuts off the discharge arrangement for the bin 34 to prevent a false indication of the amount of supplement dispensed.

Referring now more particularly to FIGS. 3 and 4, the discharge arrangement for the bin 34 will be discussed. The bin 34 includes a bottom wall 64 which extends diagonally between the front wall 44 and the rear wall 62 on approximately a angle, as shown. The bottom wall 64 has an opening 66 of a fixed size and shape near the lower end thereof. the opening being formed by lower and upper edges 68 and 70 and sides edges 72 and 74, the edge 68 being close to the rear wall 62 of the apparatus.

A valve plate 76 is located on the upper surface of the bottom wall 64 and is slidably mounted in ways or guides 78 located parallel to the edges 72 and 74 of the opening 66. The adjusting rod or member 80 is affixed to a projection 82 on the valve plate 76 and extends beyond the front wall 44 to a handle 84. The adjusting rod 80 extends through an opening 86 (FIG. 6) in a locking plate 88 which is held adjacent the front wall 44 by a locking screw 90. When the screw 90 is loosened, the locking plate 88 is loosened and the rod 80 can be moved longitudinally to adjust the position of the valve plate 76 relative to the opening 66. When the rod is pushed in. the plate 76 mot es toward the lower edge 68 of the opening to reduce the area of the opening. When the rod 80 is pulled out, the plate 78 is moved up the bottom wall 64 toward the front wall 44. to increase the area of the opening defined between the lower edge 68 thereof, portions of the side edges 72 and 74 thereof. and the forward edge of the plate 76. When the locking screw is tightened. the locking plate 88 tends to assume a true vertical position adjacent the front wall 44 and causes edges of the opening 86 to bite against the rod 80 and hold it securely in place.

A reciprocable discharge gate 92 is located adjacent the lower surface of the bottom wall 64 and is slidably mounted in ways 94 located parallel to the side edges 72 and 74 of the opening 66, below the ways 78 of the valve plate 76. The reciprocable gate 92 is reciprocated through strokes of fixed length such that a forward edge 96 of the gate extends beyond the lower edge 68 of the opening 66 when at one end of the stroke and with the edge 96 being near or back of the upper edge 70 of the opening 66 at the other end of the stroke.

To reciprocate the gate 92, a bar 98 has an ear 100 pivotally connected to the gate 92 by a suitable fastener 102. The opposite end of the bar 98 terminates in a tubular projection 104 which slidably receives a link 106 extending therethrough to a collar I08 beyond the tubular projection 104. The link 106 has a second collar 110 spaced from the tubular projection 104 with a spring 112 located therebetween. When the link 106 is moved forwardly or toward the right as viewed in FIGS. 3 and 4, the spring 112 engages the tubular projection 104 and pushes the bar 98 along with the gate 92 toward the closed position, as shown in FIGS. 3 and 4. When the link [06 is moved in the opposite direction or toward the left, the collar 108 directly engages the tubular projection 104 to move the gate 92 to the left to clear the opening 66, with the forward edge 96 of the gate being beyond the edge 70 of the opening. This connecting arrangement for the gate enables the spring 112 to be compressed as the gate moves toward the closed position in the event that some obstruction, such debris, should be caught in the opening 66, between the forward edge 96 of the gate 92 and the lower edge 68 of the opening.

The link 106 and the gate 92 can be reciprocated by a drive unit or windshield wiper drive 114 which includes an electric 12volt DC motor 116 and a suitable gear and control unit 118 forming a part thereof. A drive shaft 120 extends from the gear unit 118 perpendicular to the bottom wall 64, as shown in FIG. 4. A crank arm 122 is affixed to the drive shaft 120 and rotates therewith, clearing posts 124 which support and space a mounting plate 126 for the unit 118 from the bottom wall 64. A link extension 128 is pivotally connected to an end of the crank arm 122 by a pin I30 and the opposite end of the link extension is affixed to the link 106 by a weld 132.

When the motor 116 is driven, the drive shaft 120 is rotated to rotate the crank arm 122 to reciprocate the link extension 128 and the link 106 and correspondingly move the gate 92, the length of the stroke of the gate 92 being equal to twice the distance between the pivot pin 130 and the drive shaft 120. The commercially available unit 114 provides a relatively low cost and maintenance free drive for the gate 92 and further has the built-in feature that whenever the motor I16 is shut off, the gate 92 is moved back to the closed position of FIG. 3. Thus, there is no possibility of the opening 66 in the bottom wall 64 being left partially open upon the termination of operation, which could, of course, undesirably empty any remaining contents from the bin 34.

The amount of supplement discharged from the bin 34 upon each complete reciprocatory cycle of the gate 92 depends upon the position of the valve plate 76. Suitable lines or other indicia can be inscribed on the outer end portion of the adjusting rod 80 so that the operator knows that when a certain line on the rod is aligned with the locking plate 88, a particular amount of feed will be discharged for each complete cycle of the gate 92. If the operator then knows the number of reciprocations made, he will know the total amount of supplement supplied to the forage for any particular situation,

For this purpose, the metering apparatus is equipped with a cumulative counter I34 mounted on the side wall 38 of the apparatus. As shown in FIG. 5, the counter 134 has a window 136 through which suitable dials indicate the number of cycles made by the gate 92. The counter has a reset knob 138 and a depending arm 140 which advances the counter one digit upon each movement thereof from the dotted line position to the solid line position and back again.

To operate the arm 140, a counter operating rod or elongate member 142 extends through an opening 144 in the side wall 38. The rod I42 is pivotally attached to the gate 92 by an enlargement 146 and a fastener 148. As the gate 92 reciprocates, the rod 142 pivots about the fastener 148 and also pivots at the opening 144 in the side wall 38 to move substantially as shown between the solid and dotted line positions in FIG. 5. In the dotted line position ofthe rod I42, the counter arm 140 moves to the dotted position, being internally spring loaded. The counter can be reset to zero by means of the knob 138 after any predetermined period of time, and after the amount of supplement used in that period of time is determined.

The counter rod 142 also is engageable with a feeler arm 150 (FIG. 3) ofa limit switch 152 and is positioned to close the switch 152 briefly upon each reciprocatory motion of the gate 92. The switch 152 is electrically connected through a plug 154 to a remotely located, commercially available counter 156 of the subtraction type. The number of cycles desired for the gate 92 is set on dials showing through a window 158 of the counter by means of a knob 160 or other suitable manual means. The counter contains a solenoid operated upon each pulse of the switch 152 to reduce the counter number by one. When the number reaches zero, a switch in the counter is opened, the switch being con nected to the motor 116 through a junction box 162 and causing the motor to turn off at that time, The motor is connected to the IIO-volt AC power source through a converter I64 which converts the power to l2-volt DC, the conductors connecting the power supply, the transformer I64, and the junction box 162 not being shown. The motor 116 thus can be turned off automatically when the desired number of cycles of the gate 92 is reached or when the bin 34 becomes empty, as determined by the paddle 60 which controls the switch 52. If the gate 92 is open at that time, it is automatically returned to the closed position by the drive unit 114.

The meter 10, as shown, is mounted on four legs I66 held by straps I68 and fasteners I70. lfdesired, the legs can be arranged to extend above the top of the bin 34 to provide support for the auger trough 14. Hence, the legs are adaptable to a wide variety of installations and applications.

Various modifications of the above-described embodiment of the invention will be apparent to those skilled in the art and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

I claim:

1. Metering apparatus for feeding a quantity of particulate material from a source of supply to another location, said apparatus comprising a bin, at first plate, a first rod pivotally supporting said plate in said bin, a first switch outside said bin and mounted on said apparatus in communication with said first rod for said plate, an electrical outlet box mounted on said apparatus and connected to said switch, means for connecting a power supply to said outlet box and said switch for supplying power to said outlet box when said switch is closed and said plate is in a first position with the power to said outlet being off when said switch is open and said plate is in a second position, a second plate, a sec ond rod pivotally supporting said second plate in said bin and spaced from said first plate, a second switch outside said bin and mounted on said apparatus in communication with said second rod, said second switch being closed when said second plate is in a first position, and said second switch being open when said second plate is in a second position, said bin having an opening in a bottom portion thereof, a gate mounted for reciprocation across said opening, a gate motor for reciprocating said gate, means connecting a second power supply to said motor and to said second switch, said motor being on when said second switch is closed, and said motor being off when said second switch is open.

2. Metering apparatus according to claim I charac terized by a subtraction counter having a third switch electrically connected with said second switch and with said motor, said third switch being open when said counter is at a zero count.

3. Metering apparatus according to claim 2 characterized by means responsive to the reciprocation of said gate for actuating said counter.

4. Metering apparatus according to claim I characterized by means for supplying particulate material to said bin, a supply motor for operating said supply means, and means electrically connecting said supply motor to said electrical outlet box.

5. Metering apparatus according to claim 1 characterized by a generally upright baffle extending across said bin between said first plate and said second plate.

6. Metering apparatus for feeding a quantity of particulate material from a source of supply to another location, said metering apparatus comprising a bin, an outlet box mounted on said apparatus, said bin having an opening in a bottom wall thereof, a gate mounted for reciprocation across said opening, a l2-volt DC motor mounted on said apparatus and connected to said gate for reciprocating said gate across said opening, means for converting lIO-volt AC power to l2-volt DC power, means connecting said converting means to said motor for supplying l2-volt DC power to said motor. means for supplying ll-volt AC power to said outlet box and to said converting means, a valve plate, and means for moving said valve plate to change the open area of said opening.

7. Metering apparatus according to claim 6 characterized by said valve plate being slidably mounted on one side of said bottom wall and said gate being mounted on the opposite side of said bottom wall.

8. Metering apparatus according to claim 6 charao terized by said means for moving said valve plate comprises an elongate member extending to a handle located outside said bin, and a locking plate engageable with said elongate member for locking said member and said plate in predetermined positions.

9. Metering apparatus for feeding a quantity of particulate material from a source of supply to another location, said metering apparatus comprising a bin, an outlet box mounted on said apparatus, said bin having an opening in a bottom wall thereof, a gate mounted for reciprocation across said opening, a l2-volt DC motor mounted on said apparatus and connected to said gate for reciprocating said gate across said opening, means for converting llO-volt AC power to l2-volt DC power, means connecting said converting means to said motor for supplying l2-volt DC power to said motor, means for supplying llO-volt AC power to said outlet box and to said converting means, a subtraction counter electrically connected to said motor, and operating means including means pivotally connected to said gate for operating said subtraction counter.

10. Metering apparatus according to claim 9 characterized by said operating means comprises a limit switch mounted on said apparatus and engageable by said pivotally connected means.

1]. Metering apparatus for metering a quantity of particulate material, said metering apparatus comprising a bin for receiving the particulate material, said bin having a bottom wall defining an opening therein, a gate slidably mounted on said bottom wall in a position for reciprocation across said opening, a windshield wiper drive mounted on said apparatus, said drive comprising a DC motor and a gear unit, said gear unit having a drive shaft extending therefrom. means connecting said drive shaft and said gate to cause said gate to reciprocate relative to said opening when said drive shaft is driven, with said gate returning to a closed position closing off said opening when power to said motor is shut off, a valve plate, means for slidably supporting said valve plate on said bottom wall, and means for moving said valve plate relative to said opening.

[2. Metering apparatus for metering a quantity of particulate material, said metering apparatus comprising a bin for receiving the particulate material, said bin having a bottom wall defining an opening therein, a gate slidably mounted on said bottom wall in a position for reciprocation across said opening, a windshield wiper drive mounted on said apparatus, said drive comprising a DC motor and a gear unit, said gear unit having a drive shaft extending therefrom, means connecting said drive shaft and said gate to cause said gate to reciprocate relative to said opening when said drive shaft is driven, with said gate returning to a closed position closing off said opening when power to said motor is shut off, said connecting means comprising a crank arm connected to said drive shaft, link means having one end pivotally connected to said crank arm, and means pivotally connecting the other end of said link means to said gate.

13. Metering apparatus according to claim 12 characterized further by said last-named means comprises a tubular projection carried by said gate through which said link means extend, said link means having an enlargement on each side of said tubular projection, and resilient means located between said tubular projection and the enlargement closer to said motor.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 97 3 DATED August 5, 1975 INVENTOR(S) Theodore H. Grau it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below;

Column 6, line 27, after "outlefl insert -box--.

Signed and Sealed this Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (ummissiuner oflarenrs and Trademarks 

1. Metering apparatus for feeding a quantity of particulate material from a source of supply to another location, said apparatus comprising a bin, a first plate, a first rod pivotally supporting said plate in said bin, a first switch outside said bin and mounted on said apparatus in communication with said first rod for said plate, an electrical outlet box mounted on said apparatus and connected to said switch, means for connecting a power supply to said outlet box and said switch for supplying power to said outlet box when said switch is closed and said plate is in a first position with the power to said outlet being off when said switch is open and said plate is in a second position, a second plate, a second rod pivotally supporting said second plate in said bin and spaced from said first plate, a second switch outside said bin and mounted on said apparatus in communication with said second rod, said second switch being closed when said second plate is in a first position, and said second switch being open when said second plate is in a second position, said bin having an opening in a bottom portion thereof, a gate mounted for reciprocation across said opening, a gate motor for reciprocating said gate, means connecting a second power supply to said motor and to said second switch, said motor being on when said second switch is closed, and said motor being off when said second switch is open.
 2. Metering apparatus according to claim 1 characterized by a subtraction counter having a third switch electrically connected with said second switch and with said motor, said third switch being open when said counter is at a zero count.
 3. Metering apparatus according to claim 2 characterized by means responsive to the reciprocation of said gate for actuating said counter.
 4. Metering apparatus according to claim 1 characterized by means for supplying particulate material to said bin, a supply motor for operating said supply means, and means electrically connecting said supply motor to said electrical outlet box.
 5. Metering apparatus according to claim 1 characterized by a generally upright baffle extending across said bin between said first plate and said second plate.
 6. Metering apparatus for feeding a quantity of particulate material from a source of supply to another location, said metering apparatus comprising a bin, an outlet box mounted on said apparatus, said bin having an opening in a bottom wall thereof, a gate mounted for reciprocation across said opening, a 12-volt DC motor mounted on said apparatus and connected to said gate for reciprocating said gate across said opening, means for converting 110-volt AC power to 12-volt DC power, means connecting said converting means to said motor for supplying 12-volt DC power to said motor, means for supplying 110-volt AC power to said outlet box and to said converting means, a valve plate, and means for moving said valve plate to change the open area of said opening.
 7. Metering apparatus according to claim 6 characterized by said valve plate being slidably mounted on one side of said bottom wall and said gate being mounted on the opposite side of said bottom wall.
 8. Metering apparatus according to claim 6 characterized by said means for moving said valve plate comprises an elongate member extending to a handle located outside said bin, and a locking plate engageable with said elongate member for locking said member and said plate in predetermined positions.
 9. Metering apparatus for feeding a quantity of particulate material from a source of supply to another location, said metering apparatus comprising a bin, an outlet box mounted on said apparatus, said bin having an opening in a bottom wall thereof, a gate mounted for reciprocation across said opening, a 12-volt DC motor mounted on said apparatus and connected to said gate for reciprocating said gate across said opening, means for converting 110-volt AC power to 12-volt DC power, means connecting said converting means to said motor for supplying 12-volt DC power to said motor, means for supplying 110-volt AC power to said outlet box and to said converting means, a subtraction counter electrically connected to said motor, and operating means including means pivotally connected to said gate for operating said subtraction counter.
 10. Metering apparatus according to claim 9 characterized by said operating means comprises a limit switch mounted on said apparatus and engageable by said pivotally connected means.
 11. Metering apparatus for metering a quantity of particulate material, said metering apparatus comprising a bin for receiving the particulate material, said bin having a bottom wall defining an opening therein, a gate slidably mounted on said bottom wall in a position for reciprocation across said opening, a windshield wiper drive mounted on said apparatus, said drive comprising a DC motor and a gear unit, said gear unit having a drive shaft extending therefrom, means connecting said drive shaft and said gate to cause said gate to reciprocate relative to said opening when said drive shaft is driven, with said gate returning to a closed position closing off said opening when power to said motor is shut off, a valve plate, means for slidably supporting said valve plate on said bottom wall, and means for moving said valve plate relative to said opening.
 12. Metering apparatus for metering a quantity of particulate material, said metering apparatus comprising a bin for receiving the particulate material, said bin having a bottom wall defining an opening therein, a gate slidably mounted on said bottom wall in a position for reciprocation across said opening, a windshield wiper drive mounted on said apparatus, said drive comprising a DC motor and a gear unit, said gear unit having a drive shaft extending therefrom, means connecting said drive shaft and said gate to cause said gate to reciprocate relative to said opening when said drive shaft is driven, with said gate returning to a closed position closing off said opening when power to said motor is shut off, said connecting means comprising a crank arm connected to said drive shaft, link means having one end pivotally connected to said crank arm, and means pivotally connecting the other end of said link means to said gate.
 13. Metering apparatus according to claim 12 characterized further by said last-named means comprises a tubular projection carried by said gate through which said link means extend, said link means having an enlargement on each side of said tubular projection, and resilient means located between said tubular projection and the enlargement closer to said motor. 